Rare blood-moon events already have happened three times in the last year or so, and on Sept. 28, there will be a fourth – the final appearance in what is an even more rare tetrad sequence. Because of how close it will be to earth, this final blood moon will appear both larger and brighter than usual, giving it a special significance. Such a series of events would be noteworthy at any time, but reports of looming economic turmoil and geopolitical instability are leading some observers to speculate this “super blood moon” heralds a dramatic change in world events. Maybe...